Swingable hook carrier arm

ABSTRACT

An articulated swing machine frame for a buttonhole sewing machine in which the loop taker carrying arm located above the work is swung up for loading material in the work clamp and returned to sewing position by an air pressure device. Controls are provided for lowering the loop taker carrying arm gradually to facilitate work positioning, and for starting the machine only after the loop taker carrying arm is fully lowered.

United States Patent 1191 1 1 3,799,089 Tolle Mar. 26, 1974 [5 SWINGABLE HOOK CARRIER ARM 3,563,196 2/1971 Nicolay 112/220 [76] Inventor: Giinter Tolle, Wendelinusstr. l5, FOREIGN PATENTS OR APPLICATIONS 752 Bruchsal Germany 1,091,417 4/1961 Germany 112/258 [22] Filed: Feb. 16, 1973 Primary Examiner-George I-I. Krizmanich [21] Appl' 333078 Attorney, Agent, or Firm-Marshall J. Breen; Chester A. Williams, Jr.; Robert E. Smith [30] Foreign Application Priority Data v May 8, 1972 Germany 2222549 57 ABSTRACT 52 us. 01 112/217.3 112/220 112/258 articulated Swing machine frame for a buttonhcle [51] Int. Cl DIlSb 69/00 Sewing machine in which the loop taker carrying arm [58] Field of Search 112/258 260, 220 217.1 mated above thg is swung uP for loading mate- 7 1 12/2173 rial in the work clamp and returned to sewing position by an air pressure device. Controls are provided for [56] References Cited lowering the loop taker carrying arm gradually to fa- UNITED STATES PATENTS cilitate work positioning, and for starting the machine only after the loop taker carrying arm is fully lowered. 361,426 4/1887 Looker 112/258 3.170,425 2/1965 Becker 112/220 5 Claims, 8 Drawing Figures PATENYEDIARZS I874 SHEEI 1 0F 2 (IIIO PAIENIEBmzs m4 SHEET 2 BF 2 SWINGABLE HOOK CARRIER ARM BACKGROUND OF THE INVENTION Buttonhole sewing machines have not been built heretofore with articulated frames. In the sewing machine in which this invention finds utility, the loop taker is arranged above the work in a loop taker carrying arm which is swingable to a raised position for changing work pieces in the work clamp. For accomplishing lift of the loop taker carrying arm without disturbing the timed relation of the drive between the stitch forming instrumentalities, and for starting the machine only after the loop taker carrying arm is fully lowered, this invention provides an air cylinder for controlling the position of the loop taker carrying arm, and electrical control circuits including switches responsive to the complete closing of the swingable arm for regulating the starting of the machine operation.

In the accompanying drawings, a preferred embodiment of this invention is disclosed in which:

FIG. 1 is an elevational view of a sewing installation having this invention applied thereto and showing the machine as it is positioned during a sewing operation,

FIG. 2 is a representation of the sewing machine installation of FIG. 1 showing the sewing machine as it is positioned at completion of a sewing operation and illustrating diagrammatically the pneumatic system of this invention,

FIG. 3 is a diagrammatic representation of the pneumatic system as in FIG. 2 but showing the position of parts when the treadle is partly depressed,

FIG. 4 is a diagrammatic representation of the pneumatic system as in FIG. 2 but showing the position of parts when the treadle is fully depressed,

FIG. 5 is an enlarged perspective view showing the valve means for controlling the air cylinder,

FIG. 6 is a wiring diagram illustrating the electrical control circuits which may be used with this invention,

FIG. 7 is a side elevational view of a portion of the sewing machine of FIG. 1 showing in solid lines the bracket arm in the lowered position for sewing and showing in dotted lines the bracket arm raised for exchange of work pieces, and

FIG. 8 is a top plan view of the sewing machine of FIG. 7.

Referring to FIG. 1 of the drawings, 11 indicates a table top supported by legs 12 for accommodating a sewing machine 13. The sewing machine is of a cyclically operable variety for producing buttonholes or other closed groups of stitches. The sewing machine includes a frame base 14 which is secured in the table top 11 and in which an endwise reciprocatory needle bar 15 carrying needle 15 is joumaled. Pivotally supported on a pivot pin 16 carried in ears 17 formed on the machine frame base 14 is a bracket arm 18 which overhangs the base 14 and carries a lockstitch forming loop taker 19 in position for cooperation with a needle.

(not shown) on the needle bar in the formation of lockstitches.

An arm shaft 21 which is connected in the bracket arm to drive the loop taker, carries a sprocket 22 driven by a timing belt 23 from a sprocket 24 on a main shaft 25 in the base 14. The main shaft which is connected in the base to impart movements to the needle bar 15 and to drive control instrumentalities for the sewing machine, thus serves as common actuating means for both the needle and the loop taker.

A work clamp which is carried on the machine frame base 14 is operatively connected with feeding mechanism effective to shift the work clamp relatively to the needle and loop taker to define the shape of a tack of stitches which will result from operation of the machine.

As shown in FIG. 7, the work clamp includes an upper jaw 31 carrying a track 32 against which presses a roller 33 carried in a clevis 34 on a stud 35 slidable in the bracket arm 18. A lateral pin 36 on the stud 35 extends through a slot 37 in the bracket arm so that when the bracket arm 18 is swung up, the pin 36 upon reaching the bottom of the slot will elevate the stud 35 and by means of a lateral finger 38 on the clevis engaging beneath an arched arm 39 on the work clamp upper jaw 31, the work clamp will automatically be opened for removal and insertion of work pieces. The upper jaw of the work clamp is connected by a pivot pin 40 to a lower jaw which carries a work supporting plate 41. A base plate 42, relatively to which both jaws of the work clamp are shiftable, is connected by a pivot pin 43 to the ears 17 of the machine frame base so that the entire work clamp assembly 30 may be swung up when the bracket arm 18 is elevated, for instance, to provide access to the needle for threading.

Also carried on the main shaft 25 is a driving pulley 45 which is connected by a belt 46 with a pulley 47 on a power transmitter 48. Although the devices of this invention are compatible with any conventional power transmitter, the transmitter illustrated in the accompanying drawings is of a known type which comprises an electric motor with associated clutch and brake unit, preferably electrically controlled, whereby the drive pulley may be started and stopped accurately in predetermined angular positions of rotation.

As shown in FIG. I, an operator influenced treadle 50 is provided on a cross brace 51 between the table legs 12. By operating the treadle, the machine operator can control the raising and lowering of the sewing machine bracket arm 18 for removal and insertion of work pieces in the work clamp 30 or for threading the needle. Moreover, the treadle is the instrumentality by which the operator can initiate cycles of sewing machine operation.

The treadle 50 is connected by means of a rod 52 to an operating rock arm 53 secured fast on a rock shaft 54 joumaled in a support bracket 55 arranged beneath the table top 11. A spring 56 acting between the support bracket 55 and the rod 52 biases the treadle into a raised position. The rock shaft carries two cam arms 57 and 58 arranged to depress the operating plungers 59 and 60 of a pair of pneumatic valves 61 and 62 respectively, which are secured on the support bracket 55.

It is the function of the pneumatic valves 61 and 62 to control the delivery of compressed air toand from a pneumatic motor provided by an air cylinder 63 which influences raising and lowering of the sewing machine bracket arm 18.

The air cylinder 63 is pivotally supported as at 64 to a lateral extension 65 of the sewing machine frame base 14 and the piston 66 of the air cylinder has a piston rod 67 which is pivotally connected as at 68 to a rigid arm 69 projecting from the bracket arm 18. The air cylinder 63 is of the double acting type including conduits 70 and 71 for directing compressed air selectively to either side of the piston 66.

For accurately determining the lowered position of the bracket arm 18, an abutment stop member 80 is secured to the bracket arm in position for engagement with one of the ears 17 of the machine frame base 14 when the bracket arm is lowered. As shown in FIG. 7, the bracket arm 18 is preferably formed with a slot 81 in which the abutment stop member is secured by a fastening screw 82 passing through one extremity 83 of the stop member. The stop member is formed with a reduced central portion 84 which lends flexibility to the stop member and an adjusting stud 85 threaded through the bracket arm engages and deflects the free extremity 86 of the abutment stop member a selected distance from the bracket arm 18. The free extremity 86 of the stop member provides an adjustable abutment surface engageable with the main frame ear 17 to provide a fine adjustment of the lowered position of the bracket arm.

As shown diagrammatically in FIG. 2, the pneumatic valve 61 is preferably a spring-returned two-position valve which, in normal condition of the valve, operatively connects a supply conduit 90 from a source of compressed air to the conduit 70 leading above the piston 66 to force the sewing machine bracket arm into raised position. The valve in the normal condition also operatively connects the conduit 71 leading beneath the piston 66 to an exhaust conduit 91 open to the atmosphere. In the normal condition, therefore, the bracket arm 18 will be held in raised position by the air cylinder 63. The cam arms 57 and 58 are timed with respect to each other such that the cam arm 57 will depress the plunger 59 of the valve 61 before the treadle is completely depressed and before the cam arm 58 depresses the plunger 60 of the exhaust valve 62.

FIG. 3 illustrates diagrammatically the position of the parts with the valve 61 shifted but before the cam arm 58 depresses the plunger 60 of the valve 62. In this position, the valve 61 will connect the supply conduit 90 with the conduit 71 leading beneath the piston 66 so that pressure will be exerted to lower the bracket arm 18. The conduit 70 leading above the piston 66, however, will be connected to an intermediate conduit 92 leading to the exhaust valve 62 which in the normal spring biased condition as shown in FIG. 3 blocks the intermediate conduit 92 from an exhaust conduit 93 open to the atmosphere. As a result, a back pressure will build up against the top of the piston 66 and lowering of the bracket arm 18 will be damped and will occur slowly so that the operator can accurately position work in the work clamp. If the operator is not satisfied with the positioning of the work in the work clamp, the treadle may be released so that the bracket arm 18 will be raised and the work may be re-oriented.

When the treadle 50 is fully depressed, as shown diagrammatically in FIG. 4, not only is the valve 61 maintained in the position shown in FIG. 3, but the cam arm 58 will engage and shift the plunger 60 of the exhaust valve 62 into the position shown in FIG. 4 connecting the intermediate conduit 92 to the exhaust conduit 93 and resulting in a rapid movement of the sewing machine bracket arm 18 into completely lowered position.

As best shown in FIGS. 7 and 8 a normally open electrical switch 100 provides a sensing means which is arranged preferably on a bracket 10] secured to the machine frame base 14 in a position so that the switch will assume a closed position in response to movement of the piston rod 67 when it moves up to shift the rigid arm 69 on the bracket arm 18 into completely lowered position of the bracket arm.

A similar normally open electrical switch 110 provides a sensing means which is arranged preferably on the support bracket 55 in a position so that the switch will be closed when the rock arm 53 is lowered corresponding to the completely depressed position of the treadle 50.

The two electrical switches and influence starting of the sewing machine which can occur only when both switches are held closed.

As shown in the electrical diagram in FIG. 6, the.

switches 100 and 110 are wired in series with the coil of a relay so that the relay will be energized only when both switches are held closed. When the relay 120 is energized the normally open contacts 120A, 120B, 120C and 120D of relay 120 will be closed. Contacts 120A electrically replace the treadle influenced switch 110 so that the machine will continue to operate even if the treadle is released. Contacts 120B energize the coil of an electric clutch in the power transmitter 48 starting the sewing machine. Contacts 120C energize the coil of an electric solenoid which is on the pneumatic valve 61 and serves to hold the valve in the position illustrated in FIGS. 3 and 4 despite release of the treadle. By holding the valve 61 as shown in FIGS. 3 and 4, the solenoid 140 maintains the electric switch 100 closed. Contacts 120D prepare for operation a circuit containing the coil of a relay which operates later in the sewing cycle to effect stopping of the sewing machine.

In series with the coil of the relay 150 and the contacts 120D is a normally open electric switch which is associated with the sewing machine and is closed in response to the approaching completion of a stitching cycle as by a cam or the like (not shown). When the relay 150 is energized, the normally open contacts 150A, 1508 and 150C of relay 150 will be closed. The contacts 150A hold the relay 150 energized even if the switch 160 is thereafter opened. The contacts 150B energize the coil of an electric slow speed brake which acts to slow the pulley 47 to a controlled low speed. The contacts 150C energize the coil of a counting relay which measures a predetermined extent of rotation of the pulley 47 following which the normally open contacts 180A of counting relay 180 are closed.

Indicated at is a commutator associated with the sewing machine and preferably set so as to complete an electrical circuit upon each occurence of a predetermined position of the sewing machine main shaft 24, as for instance, when the needle reaches lowest position. With the contacts 180A closed, the coil of an electric stopping brake 200 in the power transmitter will be rendered effective in response to sensing of the predetermined sewing machine position by the commutator 190.

Normally closed contacts 1805 of the counting relay 180 are located in series with the relay 120, and when contacts 1808 are opened by energizing of counting relay 180, the relay 120 will be deenergized, which in turn will open relay contacts 120D to deenergize relay 150 so that the circuit will revert to the completely inoperative state as shown in FIG. 6 at the completion of each sewing cycle.

Having set forth the nature of this invention, what is claimed herein is:

l. A sewing machine having a stationary frame portion in which a needle bar is supported, a bracket arm frame portion shiftably supported relatively to said stationary frame portion and carrying a loop taker for movement bodily into and out of operative position cooperable with said needle bar in the formation of stitches, and a common actuating means for said needle bar and said loop taker, characterized in a pneumatic motor arranged to shift said sewing machine bracket arm frame portion selectively into and out of said operative position of said loop taker, operator influenced valve means shiftable into a running position for activating said pneumatic motor to shift said loop taker to the operative position, and sensing means responsive to concurrent shift of said valve means into said running position and shift of said loop taker into said operative position for rendering effective said common actuating means for said needle bar and said loop taker.

2. A sewing machine as set forth in claim 1 in which said sewing machine bracket arm and stationary frame portions are pivotally interconnected and are each provided with interengaging abutment surfaces for determining the operative position of said loop taker, and in which a flexible abutment stop member secured at one extremity to one of the sewing machine frame portions includes a free extremity defining one of said abutment stop surfaces which may be deflected by adjusting screw to a selected distance from the sewing machine frame portion to which it is secured.

3. A sewing machine as set forth in claim 1 in which the loop taker in said sewing machine bracket arm is arranged vertically above the needle bar in said stationary frame portion, and in which said pneumatic motor is arranged to act between said bracket arm and stationary frame portions to lower said bracket arm frame portion in the operative position of said loop taker.

4. A sewing machine as set forth in claim 3 in which means responsive to said sensing means are provided for maintaining said valve means in running position independently of operator influence, and sensing means is provided on said sewing machine responsive to completion of a predetermined sewing cycle for shifting said valve means out of running position.

5. A sewing machine as set forth in claim 1 in which said pneumatic motor comprises a double acting air cylinder including piston and means for introducing compressed air selectively to either side of said piston, and in which said operator influenced valve means comprises a first valve for directing compressed air selectively to either side of said air cylinder piston, and a second valve for selectively blocking exhaust from air connecting the opposite side of said air cylinder piston to the atmosphere. 

1. A sewing machine having a stationary frame portion in which a needle bar is supported, a bracket arm frame portion shiftably supported relatively to said stationary frame portion and carrying a loop taker for movement bodily into and out of operative position cooperable with said needle bar in the formation of stitches, and a common actuating means for said needle bar and said loop taker, characterized in a pneumatic motor arranged to shift said sewing machine bracket arm frame portion selectively into and out of said operative position of said loop taker, operator influenced valve means shiftable into a running position for activating said pneumatic motor to shift said loop taker to the operative position, and sensing means responsive to concurrent shift of said valve means into said running position and shift of said loop taker into said operative position for rendering effective said common actuating means for said needle bar and said loop taker.
 2. A sewing machine as set forth in claim 1 in which said sewing machine bracket arm and stationary frame portions are pivotally interconnected and are each provided with interengaging abutment surfaces for determining the operative position of said loop taker, and in which a flexible abutment stop member secured at one extremity to one of the sewing machine frame portions includes a free extremity defining one of said abutment stop surfaces which may be deflected by adjusting screw to a selected distance from the sewing machine frame portion to which it is secured.
 3. A sewing machine as set forth in claim 1 in which the loop taker in said sewing machine bracket arm is arranged vertically above the needle bar in said stationary frame portion, and in which said pneumatic motor is arranged to act between said bracket arm and stationary frame portions to lower said bracket arm frame portion in the operative position of said loop taker.
 4. A sewing machine as set forth in claim 3 in which means responsive to said sensing means are provided for maintaining said valve means in running position independently of operator influence, and sensing means is provided on said sewing machine responsive to completion of a predetermined sewing cycle for shifting said valve means out of running position.
 5. A sewing machine as set forth in claim 1 in which said pneumatic motor comprises a double acting air cylinder including piston and means for introducing compressed air selectively to either side of said piston, and in which said operator influenced valve means comprises a first valve for directing compressed air selectively to either side of said air cylinder piston, and a second valve for selectively blocking exhaust from air connecting the opposite side of said air cylinder piston to the atmosphere. 